Gravity Falls: War with the Xenomorphs
by Electivecross02
Summary: Note: This is NOT canon with the alien or predator series. Any information here regarding the aliens or predators may be false. If your an alien or predator fan, you'll know the difference. Anyway, the Xenomorph scourge has made its way to Gravity Falls. The Pines' only hope is to locate the predator weapons left by the writer of the journals.
1. Chapter 1

Chapter 1

The Pines were working their jobs at the Mystery shack. Mabel was upstairs playing cards with her pet pig, Waddles. She soon heard a strange rumbling in the attic. She ran downstairs to find Dipper.

Mabel: Dipper. I heard something in the attic.

Dipper: Mabel. I don't have time for your games right now.

He heard the rumbling in the attic.

Dipper: What was that?

The two of them walked up to the darkened attic.

Mabel: Didn't this place use to have lights?

They heard a hissing noise.

Dipper: Over there.

Dipper pulled out a flashlight and shined it towards the sound. Something slowly rose up. It was eight feet tall with an elongated domed skull, and a lack of eyes. It had a skeletal human body, four fingered hands, four tubes protruding from its shoulders, and dinosaur like legs. It also had a long spinal tail with a sharpened end. It walked over to the two kids. They were paralyzed with fear. The monster's tail slowly brushed up Dipper's leg. It slowly moved its lips to reveal a row of human teeth, and the mouth opened to reveal an inner pharyngeal jaw. The smaller jaw slowly opened up, aiming to the center of Dipper's forehead. Suddenly, it was blown back by a shotgun. Their great uncle Stan had shot the creature with one of the 10 guns he owned. The creature's yellow-green blood began to melt into the floor, being composed of acid.

Stan: You kids ok?

Mabel: Yeah. Dipper?

Dipper: That creature. I feel like I've seen it before.

Soos, the shack's custodian, soon ran up.

Soos: Mr. Pines! There's something melting through the ceiling down there and into the floor. And it scared off all of our customers.

In their room, Dipper was looking through his journal with the number 3 on it.

Dipper: Hey Mabel. Look at this.

Mabel looked over at the book.

Dipper: It's that thing from earlier. I knew I saw this before. It says here, "In my investigations, I had discovered a sentient alien race of incredibly hostile creatures. I called them Xenomorphs, meaning 'strange forms'. These monsters are man's worst nightmare. They capitalize on all of our greatest fears. Fears of the unknown, disease, sexuality, predation, and dehumanization. It has always been an absolute mystery to me as to where these creatures came from. It's still a mystery to me as to what they are. They have feminine bodies, but they have a masculine behavior. They could be male, female, neither or both. Their maneuverability is unmatched, able to cling to any surface and sprint incredible distances in quick bursts of speed. They have no eyes, and therefore rely on their senses of smell and touch. Their methods of reproduction are extremely shocking. First, a single egg hatches spider creatures called, 'Facehuggers.' They attach to the hosts face and insert an embryo in their body for a certain period of time. The creature soon detaches and dies, but the embryo grows into a baby which violently erupts from the rib cage, killing the host. Afterwards, the baby grows to an adult in a matter of hours, gaining the physical properties of the host."

Mabel: Ok then. That's disgusting.

Dipper: It is. If the eggs spawn the Facehuggers, and the Facehuggers spawn the Xenomorphs, then what spawns the eggs?

Mabel: It's another mystery.

Dipper: One that puts all of Gravity falls in danger.


	2. Chapter 2

Chapter 2

Mabel and Dipper were walking over to the cemetery.

Mabel: What are we doing?

Dipper: The journal said that there were ancient aliens called Yautja. They hunted Xenomorphs for sport. The writer of the journals had stolen and hidden a supply of their weapons. I'm looking for a secret door to the hiding place.

Mabel took the journal and saw the page on the Yautja.

Mabel: "Thousands of years ago, the planet was host to alien hunters I call the Yautja. They hunted the Xenomorphs using technology advanced far beyond our own. They came here to this planet, and taught the civilizations to build. In exchange, the humans gave sacrifices to spawn the Xenomorphs for the Yautja to hunt. I encountered one that had died in combat, and took all of its weapons. I hid them in this location."

A map showed the location of the weapons.

Dipper: Exactly. Their weapons are the only thing I can use to defend this town.

Mabel: Are you sure? It says that the weapons will turn you into a Yautja if you wear them too long.

Dipper: That's a risk I'm willing to take.

Mabel saw some slime on one of the headstones.

Dipper: Found it!

He pushed down one of the headstones as a secret passageway opened. It was a dark tunnel lit with torches on the walls.

Dipper: Be careful.

They walked into the tunnel. They heard the same hissing from before. They looked behind to see two Xenomorphs chasing them.

Dipper: Run!

The two of them ran all the way to the end of the tunnel. At the end, there were Yautja wrist devices, a Plasma gun, a bio mask, a spear, shurikens, proximity mines, and special armor. The two Xenomorphs dropped down and stared down Mabel. Suddenly a plasma bolt blasted one back into pieces. Another plasma bolt hit the other and killed it. Dipper was wearing the mask and the plasma gun on his shoulder.

Mabel: Thanks! What are you wearing?

Dipper: The Yautja armor.

Dipper took all the gear and locked it in. He locked on the wrist devices on his wrists, put the spear on his back, put the two shurikens and proximity mines on his belt, and put the armor on over his body. He learned how to work the technology quickly, and he and Mabel ran up to the surface.

Mabel: That stuff looks cool.

Dipper: You think this is cool, watch this.

His whole body suddenly disappeared as the eyes of the helmet flashed.

Mabel: Woah! Where did you go?

He reappeared behind her and scared her.

Dipper: Classic.

Mabel: Shut up.


	3. Chapter 3

Chapter 3

Dipper and Mabel went to the Shack to warn everyone. Wendy was reading a magazine at the front desk.

Wendy: Woah. Dipper. What are you wearing?

Dipper: There's something coming to Gravity Falls. An alien army is going to tear apart the people of Gravity falls, and this armor will help us stop it.

Wendy: Do they look like that?!

A Xenomorph burst through the window. Rather than kill the people inside, it attacked Dipper. It pinned him into a wall and began trying to attack him with its inner jaw. He struggled to break free, but was too weak to break free. He suddenly began to increase in strength as he forced off the Xenomorph's hand. He pushed his hand all the way to the neck of the Xenomorph, grabbed it, and threw it into the wall.

Mabel: Woah! Where did that come from?

The Xenomorph recovered and stood to face Dipper. It attacked with its tail, whipping and cracking the bladed end. Dipper blocked the attacks with his wrist blades. He grabbed the tail and used it to to throw the alien away. He fired his plasma caster at the creature and killed it.

Wendy: Dipper? What happened? You picked that thing up like it was nothing.

Dipper: Oh no. It's already happening. The longer I stay in this thing, the more alien I become. We need to find where the aliens are coming from, and we need to do it now.

Stan: Dipper! Me and Soos saw the whole thing! That was great! You have our support for this thing.

Dipper: Thanks.

They heard screaming coming from town.

Wendy: Oh, crud! My friends are out there!

Dipper: Follow me.

The group ran to the middle of town, where the saw the Facehuggers entangling the citizen's faces.

Dipper: Facehuggers!

Wendy: Robbie?

Robbie: Wendy?

A facehugger grabbed his face.

Wendy: Dipper! Can't you pull it off of him?

Dipper: Not with out pulling his whole face off.

Another one tried to entangle Mabel's face, but Dipper cut it in half with a shuriken. It quickly swiped around and returned to his hand.

Stan: Nice reflexes.

Dipper: Thanks. Duck.

He fired a plasma bolt over their heads at an attacking Facehugger.

Stan: How do you even know where they are?

Dipper: My mask is equipped with a vision mode that lets me see Xenomorphs.

Multiple Xenomorphs jumped in and dragged the entangled victims to a hidden area.

Wendy: What are you waiting for? Kill them.

Dipper: No. They need to be observed, before they can be killed.

Mabel: Dipper. Are you crazy?! Kill them!

Dipper: Right. Right. Sorry. I don't know what came over me.

Soos: Well, kill those things!

Dipper: It's too late. We lost them.

Dipper soon realized that he was standing over them.

Dipper: Did you guys get smaller, or did I get taller?

Stan: You definitely got taller.

They heard a gut-wrenching screech.

Soos: What was that, dude?

A large Xenomorph appeared. It was about 10 feet tall with the most notable feature being a crown like head crest. It's screech called forth a group of Xenomorphs with ridged skulls in place of the domed skulls.

Dipper: You guys stay back. It's too dangerous for you to stay here.

He started blasting away the smaller Xenomorphs with his plasma caster. He pulled out his spear and used it to battle the larger Xenomorph. It smacked the spear out of his hand, and he grabbed its arms. He slammed its head into the floor and kicked its jaw out. He stabbed it in the head with his blades multiple times, killing it. He pulled the head out of the crest and put it in the air, letting out a victory roar.


	4. Chapter 4

Chapter 4

The group was in the mystery shack.

Mabel: Dipper. What happened to you out there? You took down that big Xenomorph like it was some kind of trophy.

Wendy: And you treated the smaller ones like you were hunting them.

Soos: And to top it all off, when you killed that thing, you did that weird victory roar, and kept it's head as a trophy.

Dipper: It's the armor I'm wearing. The longer I keep it on, the more like the Yautja I become.

The news came on.

Reporter: This is Toby Determined of the Gravity Falls news. Gravity Falls is being attacked by strange alien monsters. They're attacking everybody here!

The camera cut off.

Dipper: You guys stay. I'll take care of those guys.

Stan: We're a family, Dipper. We do this together. We can use my guns.

Everybody picked up one of Stan's shotguns and loaded them up.

Dipper: Alright. From here on out, nobody leaves this group. We stick together and we take on this enemy together.

He made a rapid, guttural clicking noise.

Mabel: Dipper, you're starting to sound weird again.

Wendy: And you're skin. Look at your skin!

Dipper looked down and saw his skin was more reptilian than normal. It had a beige-green hue to it. The most noticeable change was his hair. It had been turned into tendrils hanging over his head that looked like dreadlocks.

Stan: We have to kill every last one of these before it's too late.

Dipper did the clicking noise again, having lost the ability to humanly vocalize.

Mabel: Oh no. He's so alien, he's forgotten how to talk like a human.

In Dipper's mask, he played back that sentence, and mimicked it to Mabel's exact voice.

Dipper:"Oh no. He's so alien, he's forgotten how to talk like a human."

Soos: Ha. He can mimic people. That's cool.

Dipper gestured the group forward as they ran through the darkened streets of Gravity Falls.

Out in the city, large groups of Xenomorphs were running rampant through the city, killing everyone mercilessly. Dipper and the group arrived and attacked the Xenomorphs. Dipper used a combination of all of his weapons to kill them. He blasted one with his plasma caster, cut up two with his shurikens, beat another down with his combi stick, decapitated another two with his wrist blades, and blasted the last one with his plasma caster.

Stan: This is still Dipper, right?

Wendy: Honestly, I don't even know anymore.

A bullet suddenly hit Dipper in the body. His eyes darted to the right, and he saw Wendy's father, Manly Dan, standing there armed with a revolver.

Wendy: Dad?

Dan: Wendy! Get behind me while I kill this thing.

Wendy: Dad. That thing has been keeping us safe.

Dipper slowly approached Manly Dan, getting hit by multiple revolver bullets that bounced off of his armor. He grabbed Manly Dan by the throat and pinned him to the wall with one hand. He pulled out his wrist blades from one hand, preparing to kill Wendy's father.

Wendy: Dipper, stop! Don't do this!

Stan: The Dipper I know isn't some heartless murderer.

Soos: Don't do it, man!

Mabel: Just because you turned into one of them, doesn't mean you are one of them!

After hearing this, Dipper dropped Manly Dan on the ground and let him escape. He then growled as his eyes darted to the group. His body disappeared as his eyes flashed a yellow color.

Wendy: Where did he go?

Soos: I think we made Dipper mad.

Stan: He's going to kill us all! Run!

The whole group ran as Dipper stalked over them, looking at them through his thermal vision. He pressed some buttons on his wrist bracer, which sent a signal to the Yautja home world.


	5. Chapter 5

Chapter 5

The group was running through the empty town, ever alert of what could be lurking in the shadows. Dipper was watching them through Thermal vision, hunting them. He looked the other way, and saw a national guard unit had arrived.

Stan: Good. The army is here.

Mabel: We're saved!

Soldier: Are you ok?

Soos: Yeah. We're fine.

Wendy heard her dad calling for her.

Dan: Wendy! Over here! Help me!

Wendy: Wait. I can't leave him.

Mabel: Wendy, wait!

She ran to the origin of her dad's call. She looked everywhere, but couldn't find him.

Wendy: Dad? Where are you?

Dan: Over here!

Wendy looked up and saw Dipper. He jumped down, revealing to have mimicked Dan's voice to lure Wendy into a trap.

Dipper: "Over here".

He pulled out his wrist blades and slowly approached her. She looked behind him and gasped as a Xenomorph appeared. It tackled Dipper to the ground and prepared to headbite him. Wendy quickly blasted it back with he shotgun and killed it. Dipper cloaked and retreated.

Stan: Wendy. What happened?

Wendy: Dipper.

Soos: Well. The national guard is ready to clean up this mess. So, we'd better get going.

They went to board the APC, but were stopped by another onslaught of Xenomorphs. They were lead by another large Xenomorph, but it stood on all fours, and had an armored headdress. It rammed and tipped over the APC, preventing anyone from using it.

Stan: There went our transport.

The national guard was being killed off by all the Xenomorphs. The armored Xenomorph looked at the group and brushed its arm on the ground, preparing to charge. It charged forward, ready to crush the group. It suddenly got blown over by a blue plasma explosion. Dipper had thrown a proxy mine in the path of the armored Xenomorph. He stabbed it in the neck with his combi staff and brought it down. He looked down at the group, and three lasers shaped in an open triangle came from his helmet. The plasma gun on his shoulder came out and aimed it at the group. The laser moved up and the gun fired, hitting a Xenomorph behind the group. He jumped back away, activating his cloaking device.

Mabel: He's still in there.

Stan: What?

Mabel: Dipper. He's still in that body. Think about it. All the opportunities to kill us, and he saves us.

Stan: Well. It's too late to save him now. We need to find another way out of this city.


	6. Chapter 6

Chapter 6

The group was getting extra ammunition at a gun store.

Stan: Ok. According to this map, Gravity Falls Hospital should have a helicopter to help us evacuate on the roof.

Soos: I can fly it.

Mabel: We'll make it.

Soos: Let's go.

The group moved through the nighttime streets, slowly making their way to the hospital. When they reached the hospital, they saw it had been covered in some strange substances.

Mabel: What is all that stuff?

Wendy: Looks like a giant beehive.

Stan: I think I now what the bees are. Come on.

They moved through the hospital halls, which were covered in goo. There were people attached to the walls with holes in their chests. They saw one person without a whole in his chest.

Wendy: Robbie!

Robbie: Wendy. Kill me.

He started to spasm and shake as his chest started bleeding. A small worm burst rom his chest with the face of a Xenomorph. Wendy almost vomited at the sight.

Wendy: I hope every last one of these things die.

They made it to a working elevator. As the doors started to close, a Xenomorph forced them back open with both of its hands. It opened its mouth and Stan shoved a shotgun down its mouth.

Stan: Eat this!

He blew the head off of the Xenomorph, and some acid blood got on the side of his face, melting it partially.

Mabel: Gruncle Stan!

Stan: I'll live.

The elevator arrived on the roof and the helicopter was waiting right there.

Soos: Get him inside!

They brought him into the helicopter and loaded on board.

Stan: Let's get out of here.

Mabel: Wait. We can't leave Dipper. I'm going out after him.

Soos: Are you crazy? We have to leave now.

Mabel: I'm not leaving without him.

Wendy: I'll help you. Stan?

Stan: We're not going anywhere. Watch yourself.

Mabel: Thanks.

Mabel and Wendy walked out through the streets, calling for Dipper.

Wendy: Dipper!

Mabel: Dipper!

They walked into a building, and saw true horror. Multiple bodies hung up by their feet and skinned like deer.

Wendy: Oh, God. You don't think...

Mabel: No. He wouldn't.

Something jumped in front of them. It was almost invisible, and reappeared to be Dipper. He looked down at Mabel and Wendy.

Mabel: Dipper?

Wendy: Did you do all of this? You're sick.

He growled at her and picked her up by the neck.

Mabel: Dipper, don't!

He pointed his plasma caster at Mabel, keeping them both subdued. He dropped Wendy and turned off his plasma caster. He walked away.

Mabel: Wait! We came to get you out of here.

Dipper shook his head as he admired a human skull on his belt.

Wendy: (Whisper)Is that a human skull?

Mabel just nodded.

Mabel: What is it you're even looking for? What do you want so badly?

Dipper made a series of clicking noises.

Wendy: Yeah, I don't talk clicking.

Mabel: Wait. Are you looking for the hive? We know where it is.

Dipper stood up and prepared his gear.

Wendy: Follow us.

The group moved back to the Hive, which was located in the hospital.

Mabel: Even if we find the Hive, how do you plan on getting rid of it?

Dipper pointed to his wrist device and made an exploding gesture with his hand.

Wendy: It's a bomb. How powerful is it?

Dipper gestured the whole town.

Mabel: Oh. Once you place the bomb, we can get you out in our helicopter.

Dipper nodded. They reached the hospital and ran inside. Multiple Xenomorphs began to attack, and Dipper began to subdue them with strength and efficiency. He blasted away two, he decapitated one with his shurikens, and finished the others off with his wrist blades. They took the elevator back to the roof as Dipper prepared the bomb. They reached the roof, finding Soos and Stan still waiting at the helicopter.

Soos: Oh, dudes. You made it! What's that Dipper has?

Mabel: It's a bomb that's going to take out the whole town.

Stan: Then let's lift off.

The helicopter lurched upward and forward while Dipper dropped the bomb on the roof. It began to count down and eventually detonated into a nuclear explosion the size of 300 city blocks. All of Gravity Falls was destroyed. The shock of the blast sent the helicopter out of control as it began to crash down into the forest. Everyone survived, miraculously unscathed.

Mabel: We did it! We killed all of them!

Dipper looked down at the group and began to pull off the tubes attached to his mask, which released bursts of air. He wrapped his fingers around his mask as he pulled it off, revealing his face. It was not Dipper's face. It was reptilian with four clicking mandibles covering the mouth. There was a symbol seared into his head.

Stan: What happened to Dipper?

Sood: He looks so different.

Wendy: What's with the mark on his forehead?

He pulled out a Xenomorph finger with acid on the tip.

Mabel: Wait. What is that?

He gestured the mark, then the finger, then her.

Wendy: I think he wants to put the mark on you. And us.

He burned the mark into Mabel, Wendy, Soos, and Stan's cheeks, stating that they were warriors.

The ground suddenly began to shake. It wasn't over. From the ground, an enormous super alien burst up. It had the same headdress as the others, but was larger and had a more, regal, feminine body. It had six spikes on its back, four arms(two large, two small), and a gigantic tail.

Soos: What is that?!

Mabel: I think that's what Dipper was after all along!

Wendy: It's the Queen of the Xenomorphs!

It let out an enormous roar, seeking revenge on the people who killed her children.


	7. Chapter 7

Chapter 7

Dipper gestured the group back, wanting to battle the Queen on his own. He clicked his mask back into place, jumped into the air, twisting in a 360 spin and stabbing it in the head with his spear. He jumped over it, did a front flip, and threw his shurikens. They swooped through the air and cut up the Queen's face and neck. Just as he landed, he was knocked back by the Queen's tail breaking his plasma gun. The Queen gave chase to Wendy and Mabel through the forest. She grabbed the two of them in her hands. Suddenly, a plasma bolt blasted her in the head, knocking her over. Dipper jumped in, having converted his shoulder gun into a handheld gun. As he began helping Mabel and Wendy to their feet, a tail burst through his stomach.

Both: NO!

He was lifted up in the air towards the Queen's massive mouth. The inner mouth slowly opened, preparing to hit Dipper in the head. She was soon hit with another plasma blast in the stomach as Dipper was dropped, bleeding through the whole in his stomach. Mabel had picked up the plasma cannon, and figured out how to operate it. She charged and fired it at the Queen again, and again, and again, causing it's heavy armor to wear down and rip apart. The Queen blocked the final attack with her headdress and pinned Mabel to the ground. It was stabbed through the back of the head with Dipper's spear, with Wendy holding the spear. The mighty Queen fell dead.

Wendy: Dipper!

Mabel: Dipper!

The two of them ran to Dipper, who was spitting up a bright green, viscous fluid. Soos and Stan were standing over him.

Stan: Oh no. What am I gonna tell your parents?

Mabel: Dipper no!

Soos: He can't be dying! He's just a kid!

Wendy: Don't die on us!

Mabel and Wendy were both crying. Dipper slowly reached up and wiped their tears with his hand. His eyes slowly closed as his life faded away. Another Yautja suddenly appeared behind them, along with a giant spaceship, and a huge army of Yautja. The single Yautja was adorned with gold and jewelry, signifying his place as the Clan Leader. He looked down at Dipper's body, leaned in close on Dipper's chest, and realized he still had a beating heart. He pulled out a capsule and broke it apart, revealing two blue crystal shards. He stabbed them directly into Dipper's heart, causing him to lurch upward in pain. The whole in his chest disappeared as his eyes opened. He looked around, analyzing the situation. The Clan Leader looked over him, pulled out another Xenomorph finger with acid on the tip. Dipper kneeled to the Leader. He burned multiple marks into his head and mask, putting him in the place of the new Clan Leader. All the Yautja kneeled before him, and he lifted the head of the Queen into the air, letting out a victory roar. He prepared to board the spaceship.

Mabel: Wait. What is he doing?

Wendy: He's leaving us, for the aliens.

Soos: Didn't you see them lean down to him? This is where he belongs now.

Stan: He's a leader now, and we can't stop him.

Mabel: I guess he's right.

Dipper gave a hug to all of them, giving a last goodbye.

Wendy: We're going to miss you.

Dipper waved goodbye as he boarded the Yautja spaceship. The giant ship lurched upwards, with Dipper on the bridge of the ship in the front. He looked over the files he was given, and was told he had to find the home world to a group of larger, stronger and more powerful Predators. The Black Super Predators.

THE END


End file.
